This invention relates to an apparatus for acquiring individual workpieces from a storage bin or the like containing a plurality of randomly oriented workpieces.
There are a wide variety of assembly line operations involving the handling and processing of individual workpieces. In such operations, attempts have been made at implementing automated workpiece handling systems which involve as a necessary initial step the acquisition of individual workpieces from a supply bin. Because the workpieces are usually randomly oriented in the bin, each acquired workpiece must be viewed and properly oriented before it can be subsequently processed. Viewing is normally accomplished by a video camera which generates a video signal representative of the actual orientation of the acquired workpiece. If necessary, appropriate corrections are made to the orientation of the acquired workpiece before further processing.
The known automated workpiece handling systems have generally failed to gain commercial acceptance because of their inability to acquire randomly oriented workpieces in a reliable and consistent manner.
For example, it has been proposed to utilize a gripper supported by a flexible connection, so that the gripper can conform to a randomly oriented workpiece. However, the problem with this arrangement is that after having been elevated from the work bin, subsequent accurate orientation of the workpiece is either very difficult or impossible due to the flexibility of the connection. Moreover, because these arrangements lack the ability to sense initial contact of the flexibly connected gripper with the workpiece, lost motion is often entailed, in addition to the possibility of having a damaging collision between the gripper and/or flexible arm and the workpieces.
It has also been proposed to mount the gripper on a rigid support which can be adjusted in only a single direction. A major problem associated with such an arrangement, an example of which is disclosed in U.S. Pat. No. 3,804,270, is that the surface angles of the randomly oriented workpieces vary widely relative to the direction of movement of the gripper. Since the gripper is connected to a relatively rigid support, its freedom of movement is restricted and oftentimes is insufficient to allow the workpiece to be adequately gripped for removal from the bin. This condition, of course, is unacceptable in a commerical context.
It is an object of the present invention to provide an apparatus capable of reliably and consistently acquiring single workpieces from a bin or the like containing randomly oriented workpieces.
Another object of the present invention is the provision of an apparatus employing a flexibly supported gripper to acquire randomly oriented workpieces. A sensor generates a control signal in response to a contact force exerted by the gripper on a workpiece. This control signal may be employed to activate the gripper and/or to control movement of the apparatus into and out of the storage bin.
A further object of the present invention is the provision of an apparatus which is capable of locating each acquired workpiece in a locked position at which its orientation can be determined automatically. Additional objects and advantages of the present invention will become evident in view of the following detailed discussion.